Pipe coupling tools

ABSTRACT

Pipe coupling system and method in which a tapered wall is formed on one of two tubular pipe members for press-fit engagement with a wall of the second pipe member, and the two pipe members are pressed together in an axial direction to bring the tapered wall and the other wall into direct press-fit engagement with each other. The two pipe members can, for example, be a length of copper water pipe and a copper pipe fitting, and in certain disclosed embodiments, the pipe members are drawn together by a tool having axially movable jaws which engage the pipe members and are driven together in the axial direction by an actuator and linkage which move in a perpendicular direction.

This is a division, of application Ser. No. 07/872,715 filed Apr. 23,1992 which is a continuation-in-part of Ser. No. 07/541,308, filed Jun.21, 1990 now abandoned; a continuation-in-part of Ser. No. 336,671,filed Apr. 11, 1989, now U.S. Pat. No. 5,064,225; a continuation-in-partof Ser. No. 179,062, filed Apr. 8, 1988, now U.S. Pat. No. 4,819,969.

This invention pertains generally to the coupling of tubular elementsand, more particularly, to a coupling system and method for copper waterpipes and the like.

Copper water pipes and fittings employed therewith are commonly solderedtogether. This process requires heat which is typically provided by atorch with an open flame, and this poses a fire hazard where combustiblematerials are present, for example, in houses with wood framing. Thisproblem is of even greater concern in older structures where the woodhas dried out and is more readily combustible.

Another problem with the soldering of copper pipes is the concern aboutpossible poisoning from materials such as lead which are present in thesolder. To avoid such poisoning in recent years, solders have been madewhich do not contain lead, but these solders tend to be relativelyexpensive.

It is in general an object of the invention to provide a new andimproved system and method for joining tubular elements such as copperpipe together.

Another object of the invention is to provide an new and improved systemand method of the above character which overcome the limitations anddisadvantages of techniques heretofore utilized for joining suchelements together.

These and other objects are achieved in accordance with the invention byforming a tapered wall on one of two tubular pipe members for press-fitengagement with a wall of the second pipe member, and pressing the twopipe members together in an axial direction to bring the tapered walland the other wall into direct press-fit engagement with each other. Thetwo pipe members can, for example, be a length of copper water pipe anda copper pipe fitting, and in certain disclosed embodiments, the pipemembers are drawn together by a tool having axially movable jaws whichengage the pipe members and are driven together in the axial directionby an actuator and linkage which move in a perpendicular direction.

FIG. 1 is a fragmentary sectional view of one embodiment of a couplingaccording to the invention.

FIG. 2 is a table of dimensions for coupling sleeves of the typeillustrated in FIG. 1 for use with tubular elements of different sizes.

FIG. 3 is an exploded view of another embodiment of a coupling accordingto the invention.

FIG. 4 is a sectional view of the assembled embodiment of FIG. 3.

FIG. 5 is an exploded view of another embodiment of a coupling accordingto the invention.

FIG. 6 is a sectional view of the assembled embodiment of FIG. 5.

FIG. 7 is a top plan view of one embodiment of a tool for use inassembling a pipe joint in accordance with invention.

FIG. 8 is a side elevational view of the embodiment of FIG. 7, showingthe tool in a first operational position with some pipe fittings.

FIG. 9 is a view similar to FIG. 8, showing the tool in a secondoperational position with the pipe fittings.

FIG. 10 is a centerline sectional view of another embodiment of a toolfor use in assembling a pipe joint in accordance with the invention,showing the tool in a first operational position with some pipefittings.

FIG. 11 is a view similar to FIG. 10, showing the tool in a secondoperational position with the pipe fittings.

In FIG. 1, two tubular elements 11, 12 of different diameters are joinedtogether by a coupling sleeve 13. The coupling sleeve has an axiallyelongated body 16, with a conically tapered outer wall 17 and aconically tapered inner wall 18 disposed concentrically of each other.The diameter and the angle of taper of outer wall 17 are selected toprovide a press fit with the inner wall of the larger tubular section tobe joined by the sleeve, and the diameter and the angle of taper ofinner wall 18 are selected to provide a press fit with the outer wall ofthe smaller section of tubing to be joined by the sleeve.

Examples of suitable dimensions for coupling sleeves for joining tubularelements of different sizes together are given in the table of FIG. 2.All of the dimensions in this table are in units of inches, except theangles which are in degrees. The tubular elements which are included inthis table are utilized in a yagi antenna as described in greater detailin U.S. Pat. No. 4,819,969 which has now issued on the parentapplication. Similar considerations apply, however, in designingcouplings for use with tubular elements of other materials anddimensions and for use in other applications.

In the first line of the table, for example, the larger tubular element11 has an inner diameter of 2.75 inches, and the coupling sleeve has anouter diameter of 2.74 inches at its smaller end and an outer diameterof 2.7669 inches at its larger end. When the sleeve is pressed into thetubular section, the end portion of the tube is expanded or flaredslightly by the sleeve.

In this same example, the smaller tubing section 12 has an outerdiameter of 1.66 inch, and the coupling sleeve has an inner diameter of1.663 inch at its larger end and 1.6512 inch at its smaller end. Whenthe sleeve is pressed onto the end portion of tubular section 12, theend portion is compressed or tapered slightly.

The coupling sleeve preferably has a length on the order of 2-3 timesdiameter of the diameter, and in the example given in the first line ofthe table, the sleeve has a length on the order of 5.375 inches andprojects about 0.25 inch from the ends of the tubular sections.

It has been found that the best results are obtained when the outer wallof the coupling sleeve has a greater angle of taper than the inner wallof the sleeve. More specifically, it has been found that the angle oftaper of the outer wall should be on the order of two times the angle oftaper of the inner wall. Thus, for example, in the example given in thefirst line of the table of FIG. 2, the outer wall of the sleeve has anangle of taper of 0.2867°, and the inner wall has an angle of taper of0.1258°.

It is also desirable that the coupling sleeve have a sufficient wallthickness to prevent deformation of the sleeve when it is pressed intoand onto the elements to be joined together. Thus, in the example fromthe first line of the table, the sleeve has an average wall thickness onthe order of 0.545 inch, whereas tubular members 11, 12 have wallthicknesses of 0.125 and 0.202 inch, respectively.

The coupling sleeve can be fabricated of the same material as theelements to be joined together, e.g. aluminum, or any other suitablematerial.

The press fitting by which the tubular elements and the coupling sleeveare joined together is conveniently done by pressing the sleeve intoposition on the smaller tubing section first, then pressing the sleeveinto position within the larger section. This method of assembly has theadvantage that the sleeve can be engaged directly by the press at alltimes, which means that the sleeve can be positioned as desired on thesmaller tubing section and then pressed to the desired position withinthe larger section without disturbing the position of the sleeve on thesmaller section. Any other suitable method or order of assembly can, ofcourse, be employed.

FIGS. 3 and 4 illustrate the use of a coupling sleeve 21 for joiningtogether two tubular elements 22, 23 of similar diameter. These elementsmight, for example, be two lengths of copper pipe of the type commonlyemployed in a domestic water supply system.

Coupling sleeve 21 has a cylindrical outer wall 26 and a pair ofoppositely tapered inner walls 27, 28. Each of the tapered walls has alength on the order of 1.5 times the outer diameter of the pipes to bejoined to the sleeve and an angle of taper A which preferably is nogreater than about 8.0° and can, for example, be on the order of 3.0°.The internal diameter of the sleeve at the ends of the sleeve issomewhat greater than the outer diameter of tubular elements 22, 23, andthe internal diameter toward the center of the sleeve is somewhatsmaller than the outer diameter of the tubular elements. Thus, when thetubular elements are pressed axially together with the coupling sleeve,they form a tight press-fit as in the other embodiments.

The end portions of tubular elements 22, 23 are not tapered, althoughthey are provided with a small chamfer 29, e.g. 0.5°, which is helpfulin forming a good seal between the tubular elements and the sleeve ifthe tubing has a longitudinally extending seam, as copper pipe and othertubing often does. If the tubular elements do not have a seam, thechamfer is not necessary and can be omitted.

Alternatively, the sleeve can have straight walls, and the tapers can beformed on the tubular elements. It is also possible for both the tubularelements and the sleeve to be tapered. However, for most applications,the simplest and most convenient embodiment is the one in which thesleeve is tapered and the tubular elements are not.

Radial flanges 31 are formed at the ends of sleeve 21 to facilitatepressing the sleeve and the tubular elements together. These flangesprovide axially facing surfaces which are readily engaged by press orother tool which is utilized to assemble the coupling.

FIGS. 5 and 6 illustrate the invention in connection with a street elbow32 which joins pipes 33, 34 together at an angle of 90°. The streetelbow has an L-shaped body with an internal taper 36 at one end and anexternal taper 37 at the other. The outer end of the internal taper 36has a diameter slightly greater than the outer diameter of the pipe 33which is connected thereto, and the inner end of this taper has adiameter slightly less than the outer diameter of the pipe. Similarly,the outer end of the external taper 37 has a diameter slightly smallerthan the inner diameter of the pipe 34 which is connected thereto, andthe inner end of this taper has a diameter slightly greater than theinner diameter of the pipe. Each of the tapers preferably has an angleless than about 8.0°, with an angle on the order of 3.0° being suitablefor many applications. A street elbow is often utilized in combinationwith another fitting such as a tee or another elbow, in which case pipe34 would be part of the other fitting rather than being a separate pipe.

A radial flange 38 similar to flanges 31 is provided at the internallytapered end of the elbow to facilitate assembly of the coupling to pipe33, and a chamfer 39 similar to chamfer 29 is provided at the end ofpipe 33.

Although the invention has been illustrated with specific reference toonly two pipe fittings, namely a coupling sleeve and a street elbow, itis equally applicable to most other types of fittings, including tees,male and female adapters, end caps, and the like. It is also possible tocouple two sections of pipe together in a similar manner by providingone or both of them with a suitable taper.

FIGS. 7-9 illustrate one embodiment of a small, portable tool 41 forpressing copper pipes and fittings together with the force required toform the press-fit joints. This tool has a pair of jaws 42, 43 forengagement with the pipe and fitting. The jaws are mounted on a pair ofparallel arms 44, 46 which are linked together by collapsible linkages47 which permit the arms to move toward and away from each other. Thejaws pivot between the closed position shown in full lines in FIG. 7 andthe open position shown in broken lines to permit the tool to be engagedwith and disengaged from the pipes and fittings.

Each of the linkages includes two pairs of short links 48, 49 which arepivotally connected between the parallel arms and a drawbar 51 which ismovable between extended and retracted positions in a directiongenerally parallel to the arms. The drawbars are affixed to a plate 52which is slidably mounted on a frame 53. Plate 52 is connected to asecond plate 54 by rods 56 which pass freely through openings in an endplate 57 of the frame. A hydraulic cylinder 58 is connected betweenplates 54 and 57 for moving drawbars 51 between their extended andretracted positions. The drawbars are normally in their extendedposition, and extension of the cylinder moves the drawbars to theirretracted position.

Means is provided for moving parallel arms 44, 46 and the jaws carriedthereby toward each other as the drawbar moves toward its retractedposition. This means includes cam surfaces 59 on the frame 53 and camfollowers 61 on links 49. The cam surfaces are positioned on oppositesides of the frame and curve inwardly toward each other, and the camfollowers are positioned for engagement with the cam surfaces as thedrawbar is retracted. The pulling action of the drawbar on the linkagetends to collapse it, and the cam followers travelling along the camsurfaces force the parallel arms together. When the drawbar is movedtoward its extended position, it pushes on the links, moving them towardan extended position, separating the arms and jaws.

The tool is particularly suitable for use in tight places where accessto the pipes and fittings is limited. A tool for use on 3/4 inch copperpipe and fittings, for example, is only 21/2 inches square in crosssection and provides over 11/2 inches of pipe movement in a singlestroke.

In FIGS. 8 and 9, the tool is illustrated in conjunction with a pair ofpipe fittings 63, 64 and a short pipe, or nipple, 66. The fittings haveradial flanges 63a, 64a which are engaged by the jaws of the tool, andinternally tapered walls adapted for press-fit engagement with the outerwall of the pipe.

In operation, the end portions of the nipple are inserted into the endportions of the fittings, and the jaws of the tool are closed about thefittings, with the tool in its extended or open position. When thehydraulic cylinder is actuated, the jaws bear against the radialflanges, urging the flanges toward each other and pressing the fittingsinto press-fit engagement with the nipple.

When the joint has been made, the hydraulic cylinder is deactuated, thejaws are opened, and the tool is removed from the pipe.

FIGS. 10-11 illustrate another embodiment of a tool 71 for pressingcopper pipes and fittings together with the force required to form thepress-fit joints. This tool has a pair of jaws 72, 73 similar to jaws42, 43 for engagement with the pipe and fitting. The jaws are mounted onarms 74, 76 which are slidably mounted in diverging grooves 77, 78 inthe inner faces of a pair of laterally spaced blocks 79 for movementbetween extended and retracted positions, with the jaws moving apart asthe arms are extended and toward each other as the arms are retracted.The jaws are offset from the centerlines of the arms by an anglecorresponding to the inclination of the grooves so that the jaws areparallel to each other and adapted for gripping pipes and fittings whichare aligned linearly.

A double acting hydraulic cylinder 81 is mounted to blocks 79 for movingthe arms between the extended and retracted positions, with the ram ofthe cylinder being connected to inner ends of the arms by a block 82 andlinks 83.

In operation and use, cylinder 81 is actuated to move arms 74, 76 totheir extended position and thereby separate jaws 72, 73 which are thenare engaged with the pipes and/or fittings to be pressed together. Oncethe jaws have been engaged, the cylinder is actuated to retract the armsalong the converging paths defined by the grooves, thereby drawing thejaws and the pipe members together.. After the pipe members have beenpressed together, the jaws are disengaged, and the tool is removed.

Like the embodiment of FIGS. 7-9, tool 71 can apply a strong pressingforce to the pipes and fittings and is particularly suitable for use intight places where access is limited. This tool has the additionaladvantage of having fewer parts and being simpler in construction.

It is apparent from the foregoing that a new and improved tapered jointpipe coupling and tool have been provided. While only certain presentlypreferred embodiments have been described in detail, as will be apparentto those familiar with the art, certain changes and modifications can bemade without departing from the scope of the invention as defined by thefollowing claims.

I claim:
 1. A tool for pressing two pipe members together in an axialdirection, comprising a pair of jaws engagable with the pipe members, apair of arms on which the jaws are mounted, a pair of laterally spacedblocks having diverging grooves formed in opposing inner faces thereof,means mounting the arms in the grooves for movement between an extendedposition in which the jaws are separated and a retracted position inwhich the jaws are together, and an actuator connected to the arms formoving the arms between the extended and retracted positions.
 2. Thetool of claim 1 wherein the actuator comprises a hydraulic cylinder. 3.The tool of claim 1 including a pair of links interconnecting theactuator and the arms.
 4. A tool for pressing two pipe members togetherin an axial direction, comprising a pair of jaws adapted for grippingengagement with the pipe members, a pair of arms on which the jaws aremounted, a block having a pair of diverging grooves in which the armsare mounted for movement between a first position in which the jaws areseparated and a second position in which the jaws are together, andmeans including an actuator connected to the arms for moving the armsbetween the first and second positions, the grooves engaging the armswith a wedging action which forces the jaws together as the arms aremoved toward the second position.
 5. The tool of claim 4 wherein theactuator comprises a hydraulic cylinder.
 6. The tool of claim 4including a pair of links interconnecting the actuator and the arms.